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MARKETABLE SECURITIES - Narrative (Details) | 3 Months Ended |
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Mar. 31, 2019 USD ($) Position security | Mar. 31, 2018 security | Dec. 31, 2018 USD ($)
Investments Debt And Equity Securities [Abstract] |  |  |
Other than temporary impairment losses on debt securities related to credit losses | $ | $ 0 |  | $ 0
Number of investment positions in an unrealized loss position | Position | 96 |  |
Number of securities other than agencies amount | security | 0 |  |
Fair value of securities pledged as collateral | $ | $ 278,137,000 |  | $ 259,557,000
Number of securities sold | security | 0 | 0 |

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- Definition The cumulative amount of credit losses recognized in earnings related to debt securities held for which a portion of an other than temporary impairment (OTTI) was recognized in other comprehensive income (a component of shareholders' equity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=SL6284393-111563 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 8B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=82897076&loc=SL6284393-111563 + Details
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